COLLOIDAL DISPERSION Flashcards
Mixtures of two or more substances
DISPERSION
internal or discontinuous phase
DISPERSED PHASE
external or continuous phase
DISPERSION MEDIUM
common dispersion medium
WATER
COLLOIDAL DISPERSION
particle size of colloids
1 - 500 nm
COLLOIDAL DISPERSION
May be detected under ____
ultramicroscope
COLLOIDAL DISPERSION
visible in an ____
electron microscope
- Particle size is **1 nm to 500 nm (0.5 mm) **
- May be detected under ultramicroscope and visible in an electron microscope
- Pass-through filter paper but do not pass through a semipermeable membrane
- Diffuse very slowly
- Examples: Jelly, Polymers, Milk, Paint, Cheese
COLLOIDAL DISPERSION
COLLOIDAL DISPERSION
Pass-through ____
filter paper
COLLOIDAL DISPERSION
do not pass through a ____
semipermeable membrane
COLLOIDAL DISPERSION
diffuse ____
very slowly
COLLOIDAL DISPERSION
source of radiation of the ultramicroscope
LIGHT
COLLOIDAL DISPERSION
- source of the radiation of the electron microscope
- provides high resolution power
ELECTRONS
COLLOIDAL DISPERSION
possess ____ surface area
enormous
COLLOIDAL DISPERSION
possess ____ surface
specific
COLLOIDAL DISPERSION
surface area per unit weight or volume
specific surface
COLLOIDAL DISPERSION
The smaller the particle size, the ____ the surface area
greater
COLLOIDAL DISPERSION
- effective catalyst
- directly proportional to the surface area
platinum black
COLLOIDAL DISPERSION
when they increase in size, they turn from red to blue
gold solution
COLLOIDAL DISPERSION
when they decrease in size, they trun from red to yellow
Sb and As trisulfides
COLLOIDAL DISPERSION | METHODS OF SEPARATION
- A separation method, using a semi-permeable membrane
- the pore size of which will prevent the passage of colloidal particles
- permit small molecules and ions, such as urea, glucose, and NaCl to pass through
DIALYSIS
COLLOIDAL DISPERSION | METHODS OF SEPARATION
uses a semipermeable membrane of collodion or cellophane
DIALYSIS
COLLOIDAL DISPERSION | METHODS OF SEPARATION
start of dialysis: colloids & subcolloids in ____ compartment
1
COLLOIDAL DISPERSION | METHODS OF SEPARATION
upon the dialysis: ____ pass through the membrane
semicolloids
COLLOIDAL DISPERSION | METHODS OF SEPARATION
at the end of the dialysis: ____ remain in the compartment
colloids
COLLOIDAL DISPERSION | METHODS OF SEPARATION
for kidney failure, principle behind kidney failure to remove impurities from the blood
dialysis
COLLOIDAL DISPERSION | METHODS OF SEPARATION
TYPE OF DIALYSIS:
uses dialyzer
hemodialysis
COLLOIDAL DISPERSION | METHODS OF SEPARATION
TYPE OF DIALYSIS:
do not use external devices; uses peritonium
peritoneal dialysis
COLLOIDAL DISPERSION | METHODS OF SEPARATION
A separation and purification process of colloidal material that allows filtration under negative pressure (suction) through a dialysis membrane supported in a Buchner funnel.
ultrafiltration
COLLOIDAL DISPERSION | METHODS OF SEPARATION
funnel used in ultrafiltration
Buchner funnel
COLLOIDAL DISPERSION | METHODS OF SEPARATION
filtration conducted under negative pressure (suction)
ultrafiltration
COLLOIDAL DISPERSION | METHODS OF SEPARATION
hasted by use of electric potential across the membrane
electrodialysis
TYPES OF COLLOIDAL SYSTEMS
- Systems with colloidal particles that interact well with the dispersion medium forming colloidal dispersions or solutions
- has higher affinity to dispersion medium
LYOPHILIC COLLOIDS
TYPES OF COLLOIDAL SYSTEMS
Lyophilic colloids are also called as
solvent loving colloids
SOL
TYPES OF COLLOIDAL SYSTEMS | LYOPHILIC
the attachment between the dispersed phase and the dispersion medium
SOLVATION
TYPES OF COLLOIDAL SYSTEMS | LYOPHILIC
lyophilic colloids in an aqueous dispersion media.
▪ Examples are gelatin, acacia, insulin, albumin in water
hydrophilic colloids
TYPES OF COLLOIDAL SYSTEMS | LYOPHILIC
solvation in hydrophilic colloids is termed as
hydration
TYPES OF COLLOIDAL SYSTEMS | HYDROPHILIC
acacia and gelatin are ____
POLYMERS
(molecules in chain)
TYPES OF COLLOIDAL SYSTEMS | HYDROPHILIC
insulin and albumin are ____
proteins
TYPES OF COLLOIDAL SYSTEMS | HYDROPHILIC
acacia, gelatin, insulin, and albumin are ____
they are large enough to classify as colloidals
macromolecules
TYPES OF COLLOIDAL SYSTEMS | LYOPHILIC
lyophilic colloids in non-aqueous, organic solvents.
▪ Examples are rubber and polystyrene dissolved in benzene.
LIPOPHILIC COLLOIDS
TYPES OF COLLOIDAL SYSTEMS
- Composed of materials that have little attraction for the dispersion medium.
- Examples are inorganic particles dispersed in water, such as gold, silver, sulfur, silver iodide.
- These colloids do not like solvents.
- They are less stable; therefore, a stabilizing agent is often used to make this system stable.
LYOPHOBIC COLLOIDS (SOLVENT HATING)
TYPES OF COLLOIDAL SYSTEMS | LYOPHOBIC
Composed of materials that have ____ for the dispersion medium
LITTLE ATTRACTION
TYPES OF COLLOIDAL SYSTEMS | LYOPHOBIC
These colloids ____ solvents
do not like
TYPES OF COLLOIDAL SYSTEMS | LYOPHOBIC
They are ____ stable
less
TYPES OF COLLOIDAL SYSTEMS | LYOPHOBIC
uses ____ to make this system stable
stablizing agent
TYPES OF COLLOIDAL SYSTEMS
- characterized by having two distinct regions of opposing solution affinities within the same molecule or ion.
- can combine both with polar and non-polar solvent
- composed of aggregates of micelles
AMPHIPHILIC / ASSOCIATION COLLOIDS
(amphiphiles)
COLLOIDAL DISPERSION
aggregates of 50 or more monomers of amphiphiles, has a size of 50 nm
micelles
COLLOIDAL DISPERSION
concentration of monomer at which micelles are formed
critical micelle concentration (CMC)
COLLOIDAL DISPERSION
number of monomers (amphiphiles) that aggregate to form a micelle
AGGREGATION NUMBER
PROPERTIES OF COLLOIDS
- scattering of light by colloidal particles
- widely used for determining MW of colloids
- scattering can be described in terms of turbidity T
FARADAY TYNDALL EFFECT
PROPERTIES OF COLLOIDS
- Used to observe the size, shape, and structure of colloidal particles
- Has higher resolution power than optical microscope
- resolution defined in terms of d
* the smaller the d, the greater is the resolving power
ELECTRON MICROSCOPE
PROPERTIES OF COLLOIDS
FARADAY-TYNDALL EFFECT:
scattering can be described in terms of
turbidity
T
PROPERTIES OF COLLOIDS
ELECTRON MICROSCOPE:
resolution is defined in terms of
d
KINETIC PROPERTIES OF COLLOIDS
- random, erratic movement of colloidal particles
- results from the bombardment of the particles by the molecules of the dispersion medium
- velocity increases with decreasing particle size
BROWNIAN MOVEMENT
KINETIC PROPERTIES OF COLLOIDS
- Spontaneous movement from high to low concentration until uniform system is achieved
- direct results of Brownian movement
- Can be expressed by Fick’s First Law
DIFFUSION
KINETIC PROPERTIES OF COLLOIDS
DIFFUSION:
is expressed by ____
Fick’s First Law
KINETIC PROPERTIES OF COLLOIDS
- Can be described by van’t Hoff equation
- used to calculate the MW of a colloid in a dilute solution
- Colloidal particles cannot pass through the semipermeable membrane
OSMOTIC PRESSURE
KINETIC PROPERTIES OF COLLOIDS
OSMOTIC PRESSURE:
can be described by _____
van’t hoff equation
π = cRT
KINETIC PROPERTIES OF COLLOIDS
- Velocity of sedimentation is given by Stoke’s law
- a stronger force must be applied to bring about the sedimentation = use of ultracentrifuge
SEDIMENTATION
(settling)
KINETIC PROPERTIES OF COLLOIDS
SEDIMENTATION (SETTLING):
velocity of sedimentation is given by ____
stoke’s law
KINETIC PROPERTIES OF COLLOIDS
- resistance to flow of a system under applied stress
- more viscous → greater force to make it flow
- affected by shape of particles
VISCOSITY
KINETIC PROPERTIES OF COLLOIDS | VISCOSITY
SPHERICAL
less viscous
KINETIC PROPERTIES OF COLLOIDS | VISCOSITY
LINEAR
more viscous
COLLOIDAL DISPERSION
the movement of a charged surface with respect to an adjacent liquid phase is the basic principle
ELECTRICAL PROPERTIES OF COLLOIDS
ELECTRICAL PROPERTIES OF COLLOIDS
movement of charged particle through liquid under the influence of an applied potential difference
electrophoresis
ELECTRICAL PROPERTIES OF COLLOIDS
movement of liquid through a plug or membrane across which a potential is applied
electroosmosis
ELECTRICAL PROPERTIES OF COLLOIDS
creation of potential or charge when particles undergo sedimentation
sedimentation potential
ELECTRICAL PROPERTIES OF COLLOIDS
creation of potential when liquid flow through a plug or membrane
streaming potentital
ELECTRICAL PROPERTIES OF COLLOIDS
- An important measure of the charge on a particle’s surface
- High surface charge → colloidal particles repel
zeta potential
COLLOIDAL DISPERSION
- An important property of association colloids in a solution that has the ability of the micelles to increase the solubility of materials that are normally insoluble, or slightly soluble, in the dispersion medium used
- The location of the molecule undergoing solubilization in a micelle is related to the balance between the polar and nonpolar properties of the molecule
- Adding a third component, such as emulsifying agent in an emulsion, to increase solubility.
SOLUBILIZATION
COLLOIDAL DISPERSION | SOLUBILIZATION
An important property of association colloids in a solution that has the ____ of materials that are normally insoluble, or slightly soluble, in the dispersion medium used
ability of the micelles to increase the solubility
COLLOIDAL DISPERSION | SOLUBILIZATION
The location of the molecule undergoing solubilization in a micelle is related to the balance between the ____ of the molecule
polar and nonpolar properties
COLLOIDAL DISPERSION | SOLUBILIZATION
Adding a ____, such as emulsifying agent in an emulsion, to increase solubility
third component
COLLOIDAL DISPERSION
The presence and magnitude of a charge in a colloidal particles is important.
STABILITY
Stabilization is achieved by:
Providing particles with ____
ELECTRIC CHARGE
Stabilization is achieved by:
Adding small amount of electrolyte to
LYOPHOBIC SOLS
Stabilization is achieved by:
Surrounding particles with ____
PROTECTIVE SOLVENT SHEATH
Stabilization is achieved by:
adding hydrophilic sol (protective colloids) to ____
HYDROPHOBIC COLLOIDS
COLLOIDAL DISPERSION
Protective property is expressed in
GOLD NUMBER
GOLD NUMBER
The lower the gold number, the ____ is the protective ability
HIGHER
PHARMACEUTICAL APPLICATIONS OF COLLOIDS
- A colloidal gel in which water is the dispersion medium
- Used for wound healing, scaffolds in tissue engineering, and sustained-release of drugs
- Examples: alginate, gelatin, chitosan
HYDROGELS
PHARMACEUTICAL APPLICATIONS OF COLLOIDS
- Small (0.2 – 0.5 um), loaded microspheres of polymers
- Developed as carriers for vaccines and anticancer drugs
- Increase efficiency of drug delivery, release and targeting
- Examples: polystyrene, polymicrosphere
MICROPARTICLES
PHARMACEUTICAL APPLICATIONS OF COLLOIDS
- consists of an outer membrane and an inner liquid core
- formed with phospholipids
- has a phospholipid bilayer
- loaded with pharmaceutical through:
1) lipophilic compounds → lipophilic membrane
2) hydrophilic compounds → hydrophilic core
LIPOSOMES
PHARMACEUTICAL APPLICATIONS OF COLLOIDS
LIPOSOMES:
lipophilic ____
membrane
PHARMACEUTICAL APPLICATIONS OF COLLOIDS
LIPOSOMES:
hydrophilic ____
core
PHARMACEUTICAL APPLICATIONS OF COLLOIDS
- similar to liposomes but do not have inner liquid compartment
- used for delivery of hydrophobic pharmaceuticals
- single layer
- for water insoluble drugs
- nonpolar
MICELLES
PHARMACEUTICAL APPLICATIONS OF COLLOIDS
usually formed with homogeneous particles
MICROEMULSIONS
NANOEMULSIONS
PHARMACEUTICAL APPLICATIONS OF COLLOIDS
- submicroscopic colloidal drug carrier
- composed of oily or aqueous core
- surrounded by thin polymer membrane
- more optimal as carrier for unstable drugs
NANOPARTICLES